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4. A generator having a solidly grounded neutral and rated 50-MVA, 30-kV has positive, negative-, and...
3. A 200 MVA, 20 kV, 60 Hz Y-connected solidly grounded three phase synchronous generator connect...
3. A 200 MVA, 20 kV, 60 Hz Y-connected solidly grounded three phase synchronous generator connected through a 200 MVA 20/138 KV Y-Y transformer to a 138 kV transmission line. The generator reactances to the machine's own base are X-1.10 Both of the transformers Y connections are solidly grounded and its positive, negative and zero sequence series resitances are all 0.10 pu. a. What is the voltage at the terminals of the generator during the sub transient period if a...
The positive, negative and zero-sequence reactances of a 20-MVA, 13.2 kV synchronous generator are 0.3 pu,...
The positive, negative and zero-sequence reactances of a 20-MVA, 13.2 kV synchronous generator are 0.3 pu, 0.2 pu, and 0.1 pu respectively. The generator is solidly grounded and is not loaded. If a double line-to-ground fault occurs at the generator terminals, calculate: (i) The fault current (ii) The line voltages (iii) Explain the steps that was carried out in the sequence voltage changes at all buses of the system. (Do include explanations and analysis of your solutions such as use...
QUESTION 3. (a) The positive-, negative- and zero-sequence reactances of a 20-MVA, 13.2-LV synchronous generator are...
QUESTION 3. (a) The positive-, negative- and zero-sequence reactances of a 20-MVA, 13.2-LV synchronous generator are 0.3 pu, 0.2 pu and 0.1 pu, respectively. The generator is solidly grounded and is not loaded. A line-to-ground fault occurs on phase a. Neglecting all the resistances, determine the fault current. Assume V, = 120° pu. (b) Explain why a bolted single-line-to-ground fault at the sending end of a transmission line might be higher than the bolted three-phase short circuit on the same...
03 Consider the following one line diagram. The generator is rated at 25 MVA, IN has...
03 Consider the following one line diagram. The generator is rated at 25 MVA, IN has subtransient reactance of 20 %. The transmission line has a reactance of 10 The subtransient reactance of motorlis 0.345 pu where is that ol second more pu. Each motor has the following ratings. 10 MVA and 11 kV. Both transformers are rated at 25 MVA and have a reactance of 8.05% each; the transformers 1 and 2 have voltage ratio of 11/121 KV and...
Note: # 1 states line to line fault occurs, while # 2 states double line to...
Note: # 1 states line to line fault occurs, while # 2 states double line to ground fault occurs Please explain the solution thoroughly with diagrams The positive, negative, and zero sequence reactances of a 15-MVA, 11-kV, 3ph, wye-connected generator are 11%, 8% and 3%, respectively. The neutral of the generator is grounded, and the generator is excited to the rated voltage on open circuit. A line-to-line fault occurs between phases b and c of the generator while phase a...
A single line diagram of a power system is shown in Fig. 2. The system data with equipment ratings and assumed sequence reactances are given the following table. The neutrals of the generator and A-Y...
A single line diagram of a power system is shown in Fig. 2. The system data with equipment ratings and assumed sequence reactances are given the following table. The neutrals of the generator and A-Y transformers are solidly grounded. The motor neutral is grounded through a reactance Xn 0.05 per unit on the motor base. Assume that Pre-fault voltage is takin as VF-1.0 ,0° per unit and Pre- fault load current and Δ-Y transformer phase shift are neglected In the...
QUESTION 4. A single-line diagram of a power system is shown in Figure Q3 below, where...
QUESTION 4. A single-line diagram of a power system is shown in Figure Q3 below, where negative and zero-sequence reactances are also given. The neutrals of the generator and A-Y transformers are solidly grounded. The motor neutral is grounded through a reactance X.=0.05 per unit on the motor base. Prefault voltage is VF1.05<Oº per unit whereas prefault load current is zero. Take A-Y transformer phase shifts into consideration. M Line tool X, - X2 - 200 100 MVA X =...
The following are the answers: Autumn 2013 T1 G1 5 kV 50 MVA 5/20 kV 50...
The following are the answers:
Autumn 2013 T1 G1 5 kV 50 MVA 5/20 kV 50 MVA 20 kV 50 MVA X 0.1 p.u Figure A13 In the system shown, per-unit series equivalent impedances are shown for each element. Before a balanced 3-phase fault occurs in the location shown, the pre-fault current is at its rated value at 90 % lagging power factor flowing from generator G1 The generator is operating at full voltage. How much current in kA is...
2. A single-line diagram of the power system considered is shown in Figure P2a, where negative-...
2. A single-line diagram of the power system considered is shown in Figure P2a, where negative- and zero-sequence reactances are also given. The neutrals of the generator and A-Y transformers are solidly grounded. The motor neutral is grounded through a reactance Xn = 0.05 per unit on the motor base. The per-unit zero-, positive and negative-sequence networks on a 100-MVA is shown in Figure P26, 13.8-kV base in the zone of the generator. a. Reduce the sequence networks to their...
A star-connected alternator whose neutral point is solidly grounded, has an open circuit voltage of 14KV....
A star-connected alternator whose neutral point is solidly grounded, has an open circuit voltage of 14KV. The positive, negative and zero sequence impedance are j12, j4 and j2.4ohms/phase respectively. A single line to earth fault occurs on phase 'a' through a resistive object of resistance 0.8 ohms. Find a) fault current b) phase voltage of 'b' at the point of fault.
3. A 200 MVA, 20 kV, 60 Hz Y-connected solidly grounded three phase synchronous generator connected through a 200 MVA 20/138 KV Y-Y transformer to a 138 kV transmission line. The generator reactances to the machine's own base are X-1.10 Both of the transformers Y connections are solidly grounded and its positive, negative and zero sequence series resitances are all 0.10 pu. a. What is the voltage at the terminals of the generator during the sub transient period if a...
QUESTION 3. (a) The positive-, negative- and zero-sequence reactances of a 20-MVA, 13.2-LV synchronous generator are 0.3 pu, 0.2 pu and 0.1 pu, respectively. The generator is solidly grounded and is not loaded. A line-to-ground fault occurs on phase a. Neglecting all the resistances, determine the fault current. Assume V, = 120° pu. (b) Explain why a bolted single-line-to-ground fault at the sending end of a transmission line might be higher than the bolted three-phase short circuit on the same...
03 Consider the following one line diagram. The generator is rated at 25 MVA, IN has subtransient reactance of 20 %. The transmission line has a reactance of 10 The subtransient reactance of motorlis 0.345 pu where is that ol second more pu. Each motor has the following ratings. 10 MVA and 11 kV. Both transformers are rated at 25 MVA and have a reactance of 8.05% each; the transformers 1 and 2 have voltage ratio of 11/121 KV and...
A single line diagram of a power system is shown in Fig. 2. The system data with equipment ratings and assumed sequence reactances are given the following table. The neutrals of the generator and A-Y transformers are solidly grounded. The motor neutral is grounded through a reactance Xn 0.05 per unit on the motor base. Assume that Pre-fault voltage is takin as VF-1.0 ,0° per unit and Pre- fault load current and Δ-Y transformer phase shift are neglected In the...
QUESTION 4. A single-line diagram of a power system is shown in Figure Q3 below, where negative and zero-sequence reactances are also given. The neutrals of the generator and A-Y transformers are solidly grounded. The motor neutral is grounded through a reactance X.=0.05 per unit on the motor base. Prefault voltage is VF1.05<Oº per unit whereas prefault load current is zero. Take A-Y transformer phase shifts into consideration. M Line tool X, - X2 - 200 100 MVA X =...
The following are the answers:
Autumn 2013 T1 G1 5 kV 50 MVA 5/20 kV 50 MVA 20 kV 50 MVA X 0.1 p.u Figure A13 In the system shown, per-unit series equivalent impedances are shown for each element. Before a balanced 3-phase fault occurs in the location shown, the pre-fault current is at its rated value at 90 % lagging power factor flowing from generator G1 The generator is operating at full voltage. How much current in kA is...
2. A single-line diagram of the power system considered is shown in Figure P2a, where negative- and zero-sequence reactances are also given. The neutrals of the generator and A-Y transformers are solidly grounded. The motor neutral is grounded through a reactance Xn = 0.05 per unit on the motor base. The per-unit zero-, positive and negative-sequence networks on a 100-MVA is shown in Figure P26, 13.8-kV base in the zone of the generator. a. Reduce the sequence networks to their...
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